Randomly buying Spanish talent isn't a good plan. It's just an inferiority complex towards what Barca achieved in recent years. Take Isco for instance. Where does he even fit? On the left you have Ronaldo. In the center you have Özil. So they are going to play a slow, right-footed midfielder on the right wing? And that's going to improve which element of Real Madrid's play? People may have forgotten because he had a mediocre season in all the mess Mourinho created last year but Di Maria is the deadliest winger in the world when on-form. In 11/12 he was on his way to set a new assist record in La Liga before injuries stopped him halfway through. In Clasicos his lightning pace is always causing us problems on counterattacks. He tore Puyol a new one in the last Camp Nou match. So which new element does Isco exactly bring to the table that Real Madrid is lacking? It's a political buy.
And the U21 EC is completely irrelevant. Spain's first team is so stacked that they can use players like Thiago, Isco, Bartra, Montoya, Tello and De Gea for the U21s who are all Champions League experienced against infinitely more inexperienced teams. Italy was the second best team in the tournament and their whole backline consisted of Serie B players. Even Thiago looked like a God against them. Have you seen him having that kind of game in La Liga? I haven't. Only time he produced that kind of performance was in the Copa del Rey against Alaves who are a Segunda team. Germany for example could have entered the tournament with Gündogan, Götze, Draxler, ter Stegen etc. But they were all called up for the first team already so they didn't go back to the U21s.
Real Madrid is jumping too late on the bandwaggon. Spain's era is coming to an end with Xavi's decline. Thiago, Isco etc. won't reproduce that success.